H.M. King High School Castillo coached linebackers and was the defensive line coach at
Henrietta M. King High School from 1986 to 1989.
Texas A&M University–Kingsville Castillo was the
defensive line coach for
Texas A&M University–Kingsville from 1982 to 1985 and from 1990 to 1994 he was the offensive line coach. Four offensive linemen he coached ended up in the NFL:
Jermane Mayberry,
Philadelphia Eagles The
Philadelphia Eagles hired Castillo as an offensive assistant in
1995 under
Ray Rhodes. The hiring was met with surprise by players, fans, and members of the media primarily because Castillo had not coached the defensive side of the ball since he was at Henrietta M. King High School in 1989. Castillo was fired on October 16, 2012.
Baltimore Ravens On January 21, 2013, Castillo was hired as a consultant by the
Baltimore Ravens. At the time of the hiring, the Ravens were preparing to play in
Super Bowl XLVII. Castillo would officially join the coaching staff for the
2013 season as the run-game coordinator and held the job for one season, before serving as the offensive line coach from 2014 to 2016.
Buffalo Bills In 2017, Castillo was hired by the
Buffalo Bills to become the offensive line coach and run-game coordinator under new head coach
Sean McDermott. He served two seasons with the Bills before being dismissed following the 2018 season.
Michigan Castillo joined the
Michigan Wolverines coaching staff as an offensive analyst for the 2019 season. As part of his duties, Castillo worked with Michigan offensive line coach
Ed Warinner.
Chicago Bears Castillo was hired by the
Chicago Bears as offensive line coach on January 5, 2020. The move reunited him with head coach
Matt Nagy, whom he worked with in Philadelphia. He was not retained by the team following the firing of Nagy after the 2021 season.
Washington Commanders Castillo was named tight ends coach of the
Washington Commanders on February 21, 2022. He was not retained by the team following the hiring of new head coach,
Dan Quinn, in the 2024 offseason.
UCLA In March 2024, Castillo was hired by
UCLA as an offensive line coach under head coach,
DeShaun Foster.
Michigan In December 2024, Castillo was hired by
Michigan as an offensive analyst for the offensive line under head coach,
Sherrone Moore. ==Personal life==